Transcript File - Hussein El Haj Ahmad
Slide 1
Herbal Extracts with
Anti-MRSA and
Quorum Sensor
Neutralization
Activities
HUSSEIN El Haj Ahmad
SUNIL Maharjan
RATISH S. Pillai
Slide 2
MRSA causes infections:
• In hospitals including:
– Catheter-associated bacteraemia
– Surgical site infections
– Ventillator-associated pneumonia (VAP)
• In community
– patients who lack traditional MRSA risk
factors
Alp and Voss (2006); HPA (2007); CDC (2007).
Slide 3
High Global MRSA Prevalence
Canada 2.3%
China 39%
Netherlands 1%
USA 55%
Japan 74%
UK 44%
Germany 25%
France 27%
Spain 27%
Romania 61%
Cyprus 56%
Hong Kong
80%
Latin America
29%
Singapore
63%
South Africa 49%
Nigeria 21%
Australia
26%
Alpesh and Batts (2006); EARSS (2005); PHAC (1997); Collignon et al (2005).
Slide 4
% MRSA in Infections Diagnosed for
Staphylococcus aureus
MRSA Prevalence in UK Between 1990 and 2005
50
45
42
44
43
40
39
35
44
40
33
30
30
25
22
20
15
10
5
HPA
EARSS
9
2
4
0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Years
HPA (2007); EARSS (2005).
Slide 5
% MRSA in Deaths Diagnosed for
Staphylococcus aureus
MRSA Deaths in UK
90
78.2
80
68.1
70
60.6
60
50.5
49.6
58.2
50
40.3
40
72
70.4
47.2
32.5
30
20
11.8
20.6
10
NS
0
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Years
This increase may be related to improved levels of reporting
on death certificates.
National Statistics online (February 2007).
Slide 6
MRSA Resistance
• MSRA is resistant to several classes of antibiotics.
• Emerging problem: formation of tolerant biofilm
– causing chronic and recurrent nosocomial device-related
infections
• Increased demand for new anti-infectives and
novel strategies to control MRSA infections
Alpesh and Batts (2006); Rice (2006); Costerton et al., (1999); Donlan and Costerton (2002); Lewis (2001).
Slide 7
Antipathogenic Agents
– Downregulation of microbial virulence factors
– Inhibition of biofilm formation
• Those agents are known as QSI.
• Crude extract and toluene extract of garlic showed
– QSI activity against Pseudomonas aeruginosa
– Synergism with some conventional antibiotics at sublethal
concentration
• Until now garlic extract and allicin activities against
MRSA biofilms are not studied.
Watnick and Kotler (1999); Davies et al. (1998); Rasmussen (2005).
Slide 8
MRSA Market
• MRSA market of five antibiotics had increased
from 570 million USD in 2002 to 1.5 billion USD in
2006.
• To have a share in this growing market, some
pharmaceutical companies are developing newer
anti-MRSA agents in their pipelines.
– Arpida (iclaprim)
– GlaxoSmithKline (pleuromitilin)
– Astra-Zeneca (AZD1279)
• Why not to have a share in this market?
Slide 9
Aim
This research aims to study whether:
Allicin alone, allicin mixed with toluene,
toluene-, ethanol-, and chloroform- extracts
of garlic can prevent or not MRSA biofilm
formation.
Slide 10
Materials and Methods
• Clinical isolates
– Clinical MRSA isolates, MRSA control strain,
Pseudomonas aeruginosa positive control strain.
• Chemicals
– Aqueous extract of allicin, allicin + toluene,
toleuene extract of garlic, ethanol-extract of garlic,
and chloroform-extract of garlic.
• MIC and MBC
– MIC & MBC of planktonic bacteria and those in
biofilms will be determined according to BSAC
guidelines.
Slide 11
Materials and Methods
• Biofilm formation
– Plasma method
– MBECTM-HTP Assay in Calgary Biofilm Device
• Measurement of microbial count,
viability and killing in MRSA biofilms
– Microbial viable count will be determined on realtime basis by plate count and luminometry.
Slide 12
Summary
• Global increase in MRSA prevalence
• MRSA grows in biofilms thus increasing its
resistance
• Any agent interfering with QS will inhibit
biofilm formation and decrease microbial
pathogenicity.
• If allicin inhibits MRSA biofilm formation:
– it may act as QSI
– proven antimicrobial activity, promising natural
agent against serious MRSA infections.
Slide 13
THANK U
Herbal Extracts with
Anti-MRSA and
Quorum Sensor
Neutralization
Activities
HUSSEIN El Haj Ahmad
SUNIL Maharjan
RATISH S. Pillai
Slide 2
MRSA causes infections:
• In hospitals including:
– Catheter-associated bacteraemia
– Surgical site infections
– Ventillator-associated pneumonia (VAP)
• In community
– patients who lack traditional MRSA risk
factors
Alp and Voss (2006); HPA (2007); CDC (2007).
Slide 3
High Global MRSA Prevalence
Canada 2.3%
China 39%
Netherlands 1%
USA 55%
Japan 74%
UK 44%
Germany 25%
France 27%
Spain 27%
Romania 61%
Cyprus 56%
Hong Kong
80%
Latin America
29%
Singapore
63%
South Africa 49%
Nigeria 21%
Australia
26%
Alpesh and Batts (2006); EARSS (2005); PHAC (1997); Collignon et al (2005).
Slide 4
% MRSA in Infections Diagnosed for
Staphylococcus aureus
MRSA Prevalence in UK Between 1990 and 2005
50
45
42
44
43
40
39
35
44
40
33
30
30
25
22
20
15
10
5
HPA
EARSS
9
2
4
0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Years
HPA (2007); EARSS (2005).
Slide 5
% MRSA in Deaths Diagnosed for
Staphylococcus aureus
MRSA Deaths in UK
90
78.2
80
68.1
70
60.6
60
50.5
49.6
58.2
50
40.3
40
72
70.4
47.2
32.5
30
20
11.8
20.6
10
NS
0
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Years
This increase may be related to improved levels of reporting
on death certificates.
National Statistics online (February 2007).
Slide 6
MRSA Resistance
• MSRA is resistant to several classes of antibiotics.
• Emerging problem: formation of tolerant biofilm
– causing chronic and recurrent nosocomial device-related
infections
• Increased demand for new anti-infectives and
novel strategies to control MRSA infections
Alpesh and Batts (2006); Rice (2006); Costerton et al., (1999); Donlan and Costerton (2002); Lewis (2001).
Slide 7
Antipathogenic Agents
– Downregulation of microbial virulence factors
– Inhibition of biofilm formation
• Those agents are known as QSI.
• Crude extract and toluene extract of garlic showed
– QSI activity against Pseudomonas aeruginosa
– Synergism with some conventional antibiotics at sublethal
concentration
• Until now garlic extract and allicin activities against
MRSA biofilms are not studied.
Watnick and Kotler (1999); Davies et al. (1998); Rasmussen (2005).
Slide 8
MRSA Market
• MRSA market of five antibiotics had increased
from 570 million USD in 2002 to 1.5 billion USD in
2006.
• To have a share in this growing market, some
pharmaceutical companies are developing newer
anti-MRSA agents in their pipelines.
– Arpida (iclaprim)
– GlaxoSmithKline (pleuromitilin)
– Astra-Zeneca (AZD1279)
• Why not to have a share in this market?
Slide 9
Aim
This research aims to study whether:
Allicin alone, allicin mixed with toluene,
toluene-, ethanol-, and chloroform- extracts
of garlic can prevent or not MRSA biofilm
formation.
Slide 10
Materials and Methods
• Clinical isolates
– Clinical MRSA isolates, MRSA control strain,
Pseudomonas aeruginosa positive control strain.
• Chemicals
– Aqueous extract of allicin, allicin + toluene,
toleuene extract of garlic, ethanol-extract of garlic,
and chloroform-extract of garlic.
• MIC and MBC
– MIC & MBC of planktonic bacteria and those in
biofilms will be determined according to BSAC
guidelines.
Slide 11
Materials and Methods
• Biofilm formation
– Plasma method
– MBECTM-HTP Assay in Calgary Biofilm Device
• Measurement of microbial count,
viability and killing in MRSA biofilms
– Microbial viable count will be determined on realtime basis by plate count and luminometry.
Slide 12
Summary
• Global increase in MRSA prevalence
• MRSA grows in biofilms thus increasing its
resistance
• Any agent interfering with QS will inhibit
biofilm formation and decrease microbial
pathogenicity.
• If allicin inhibits MRSA biofilm formation:
– it may act as QSI
– proven antimicrobial activity, promising natural
agent against serious MRSA infections.
Slide 13
THANK U